Magneto



July 18, 1933. c, 515 1,918,562

MAGNETO Filed Nov. 27, 1931 2 Sheets-Sheet l (Ittornegr July 18, 1933- 3, 515 1,918,562

MAGNETO Filed Nov. 27, 1931 2 Sheets-Sheet 2 Patented July 18, 1933 UNITED STATES PATENT OFFICE CURT I, BEIS, OF BELOIT, WISCONSIN, ASSIGNOB TO FAIRBANKS,'MORSE & COMPANY, 01' CHICAGO, ILLINOIS, A CORPORATION 01 ILLINOIS MAGNETO Application filed November27, 1931. Serial No. 577,682.

invention relates to magnetos and particularly to magnetos of the type employing a permanent magnet rotor.

One object of my invention 1s to produce a magneto in which the over-all length of the rotor may be reduced, while for the same length of rotor a much stronger magnetic field may be obtained. ,f" Another, object is to provide a short efii- 1.5.0 cient rotor which may be assembled in fixed permanent form without bolts, screws or welding.

Still another obj'gct is to produce a rotor which may be constructed almost entirely of non-annealed steel, and in which parts may be magnetized efiiciently after the rotor is assembled.

Other objects include the production of a specialstator structure which is adapted to operate efiicientl with short rotors such as are contemplate by my invention; special pole piece structure aiming toward obtaining eflicient magnetic circuits, and numerous other objects and advantages which will be apparent to those skilled in the art, from a reading of the following specification in conunction with the accompanying drawings in which:

Figure 1 is a perspective view of one form of assembled rotor embodying my invention.

Figure 2 is a section on line 22 of Figure 1.

Figures 3 and 4 are sections taken on lines 33 and 44, respectively, of Figure 2. Figure 5 is a fragmentary section taken on line 5-5 of Figure 3.

Figure 6 is a vertical longitudinal section of one form of magneto embodying my invention, the section showing the relation between the rotor and stator pole pieces.

Figure 7 is a view partly in elevation, and partly diagrammatic showing the relation between the rotor and stator parts after they are assembled; and

Figure 8 is an enlarged detail view of a portion of the stator laminated structure.

Referring to Figure 2 of the drawings the reference character 11 designates a shaft, hav-' ing a shoulder 12 adjacent one end, a threaded portion 13 near the other end, and the usual tapered and threaded drive-end portion beyond the thread 13. Threaded over the shaft 11 and secured thereon, as by keys 14, are two non-magnetic disks or end-plates 15 and 16.. The disk 15 is imperforate, except for the shaft opening, while disk 16 contains a'plural ity of perforations or openings 17 at spaced intervals.

In contacting relation and coaxially with the disk 15, are a permanent magnet plate 18, and a non-magnetic supporting plate 19, both of which are keyed to shaft 11 by the same key that holds disk 15. The supporting plate 19 is locked to plate 18 by overhanging lugs 21 (see Figures 3 and 5) and contains perforations 22 which are in line with the perforations 17 in plate 16.

The plate 19 and disk 16 support bar magnets 23, here shown as of cylindrical form but this, while preferred, is not essential. These bar magnets abut the permanent magnet plate 18 at one end of the rotor so as to form a continuation of the magnetic circuit of this magnet, while at the other end they fit into and pass through the'perforations 17 in disk 16. i

The magnets 23 carry laminated polepieces 24 and-24 made up'ofthin iron or steel plates. Pole piece 24 surrounds the like poles of two of the magnets 23, while pole piece 24 surrounds the opposite poles of the two opposite magnets 23. Obviously each pole shoe must connect like poles in each instance and, although I have shown a two-pole structuremy invention is applicable to other arrangements.

The pole shoes 24 and 24 may contact with disk 16, but ordinarily the length of these shoes will be less than that of the magnets between plate 19 and disk 16. In such a case I provide sleeves 25 about each bar and which fill the space between the pole piecesand the plate 19. Consequently when disks 15 and 16 are drawn together the sleeves and pole pieces are compressed into a rigid fixed assembly. As here shown a gear 26 is also keyed to shaft 11 and the whole assembly is secured to the shaft .11 by a nut 27 engaging thread 13 and preferably seating in a socket 28 in the space of gear 26. In this way the entire rotor structure is held between shoulder 12 and nut The result of this arrangement is to pro- 27, and the bar magnets are accurately supduce a strong efiicient structure in which the ported in spaced relation in the perforations flux concentration is increased and the secof late 19 and disk 16. ondary voltage generated, therefore, also in- H he over-all length of the rotor is small creased. Amagneto embodying this structure because the bar magnets abut and form a conis especially applicable to use in connection tinuation of the magnetic circuit of perwith high compression engines in which a hot manent magnet plate 18. The plate'l8 may spark is essential.

be magnetized before the rotor is assembled Although I have herein shown and debut bar magnets 23 may be magnetized after scribed only one form of magneto embodying assembly by bringing their exposed ends my invention, it will be obvious that changes which project through disk 16 into direct enmay be made in the details, within the scope gagement with themagnetizing poles. In the of the appended claims, without departing usual arrangement it is necessary to magfrom the spirit and scope of the invention:

netize the poles through an air gap with con- What I claim is:

, sequent loss in efiiciency because of the high 1. A rotor for a rotating field type of magreluctance introduced into the magnetizin neto, including a shaft, a plate assembly infield. With my structure it becomes p'ractica eluding a permanent magnet plate, a nonto magnetize the oles after assemblyand t magnetic plate and locking means associated do it effectively y direct contact with the ith one f id; l i d engaging th source of ma etizin flux. other thereof, for preventing relative rota- It will be 0 vious t at by vary ng the numtional movement between said plates, a pluber of laminations in the pole pieces 24 n rality of permanent bar magnets in magnetic correspondingly varyingthe'length of slee contact withsaid magnet plate and forming 35 25, the effective lengthoI the p l p c y a continuation of the magnetic circuit therebe made to Suit y desired C9nd1t1011 S- of; and means forsecuring said plate assem- In employing rotors embodying my I B bly against rotation on said shaft. tion I prefer to make use of a stator structure 2, A rotor f a t ti fi ld t f as is lustrated in Figures 6, 7 and 8. RB- neto, including a shaft, a perforated end so i g to Figure lefernce plate detachably securedjzo said shaft, a plate fl t r 31 desfinatfis agener M31112 9 Q structure consisting of a permanent magnet mg the "$1111 @011 P Thls i g end plate, a non-magnetic plate having lugs supported on and 1s 1n ir t m gn f arranged 'to engage in looking relation said tion with tW slmllal P p q Slnce magnetplate, and a plurality of permanent these P Pieces of ldentlcal structure bar magnets spaced from each other but each only one of them Is h W abutting said magnet end plate and forming- These P Pleces are made up of m a continuation of the magnetic circuit theretions of iron or steel, and preferably comprise f d h f id magnets h i one f lt rnat long laminations 34 (S g its ends projecting through one of the perfoand short laminations 35. The long laminati i id d l t tions 34 extend throughout the length of the 3, A to for a rotating field type of pole piece into contact with bridge 32, Wlnle magneto, including a shaft; a perforated end the short ones 35 extend only a short distance l t f n ti t i l detachably or to a deflected portion or shoulder 36. Th secured to said shaft near one end thereof 45 bj t f thi arrangement is tomake the p016 a plurality of spaced permanent bar magnets, piece wider at the bottom Where it is In mageach supported at one end in a perforation netic relation with the rotor than at the top in said plate; pole shoes bridging certain of where it meets the coil bridge. This result aid magnets; a plate structure including a is accomplished y inter-sir g 11 Short :1 permanent'magnet plate secured to said shaft 50 ti 1 between each pair of long ones; and at the other end and abutting the ends of the then contracting the pole piece above point bar magnets; spacers between the plate struc- 36. In order to strengthen the structure, esture and pole shoes, and means coacting with pecially after the squeezing or contracting the shaft, spacers and end plate for clamping operation it is preferred to use thicker long the plate structure to the bar magnets, and

laminations 37 at spaced intervals. As here clamping the pole shoes in assembled relation shown every fifth long lamination is thicker. to the magnets and end plate.

I am aware that it is not new to intersperse 4. A rotor for a rotating field type of maglong and short laminations in order to inneto,including a shaft, a shoulder adjacent crease the flux concentration in the coil bridge, one end of said shaft, 9. perforate non-ma 60 but I believe I am the first to improve this netic end disc detachably secured to said combination by interspersing heavier lamishaft adjacent said shoulder, an end plate nations at intervals. These heavier laminastructure consisting of a pair of non-ma tions not only stiffen the structure, but they netic end plates detachably secured to sa1d also tend to prevent ruptures during the conshaft, one of said plates being perforated tracting process. and the other imperforate, a permanent magnet plate disposed between the pair of nonmagnetic plates and in contacting relation with said imperforate end plate, means carried by one of said plates and arranged to be locked into holding relation with another of said plates; a plurality of bar magnets disposed in abutting relation to said permanent magnet plate with their other ends carried in and projecting through the perforations in said perforated end disc; laminated pole shoes threaded over and bridging certain of the bar magnets adjacent said (perforated end disc; spacer sleeves carrie by said bar magnets between the pole shoes and plate structure; and means coacting with said shaft, sleeves, and disc for clamping the plate structure to the bar magnets; and for clamping the pole shoes in fixed assembled relation to the bar magnets and disc.

5; A rotor for a rotating field type of magneto, including a shaft having a shoulder portion, a non-magnetic end plate with. spaced apertures therein, and detachably positioned: adjacent the shoulder portion; an imperfo-' rate permanent magnet plate; a plurality of bar magnets, each of said magnets having one ofits ends projecting through one of said apertures and having its other end abutting said permanent magnet plate and forming a continuationof. the magnetic circuit thereof; pole shoes bridging certain of said bar magnets, spacer members between the pole shoes and said magnet plate, means for:

securing said plates against rotation relative to said shaft, and permitting limited movement of said plates along said shaft, for assembly purposes. v

6. A stator structure for magnetos, in-

tions, each group consisting of alternate long and short laminations held in close contact, the longer laminations being extended beyond and deflected from the planes of the shorter laminations, and sheets of heavier material disposed at intervals between the longer laminations and being coextensive therewith, said sheets being shaped to conform substantially to the shape of the longer laminations the elements of each group being so assembled as to produce a port-ion of greater width near one end of the group, and a portion of lesser width at the opposite end of the group; the groups being related in assembly with the portions of lesser Width assembled adjacent each other whereby to effect a flux concentration at the group ends of lesser width.

8. A rotor for a rotating field type of magneto, including a shaft, a permanent magnet plate; a plurality of bar magnets abutting said magnet plate and forming a continuation of the magnetic circuit thereof; laminated pole pieces embracing certain of said bar magnets at one end thereof, spacers carried by said bar magnets between said pole pieces and said permanent magnet plate; and perforate non-magnetic plates at each end of said bar magnets,each magnet thereof having its end portions seated in a perforation in each non-magnetic plate to form a rigid assembly.

9. A rotor for a rotating field type of magneto, including a shaft, a perforate non-magnetic member on said shaft, a plurality of cluding an aggroupment of compressed lami nations, one end of the group consisting of a greater number, and the opposite end of a lesser number of laminations, the laminations adjacent each other being closely compressed at the respective ends of the group whereby there results a flux-concentrating portion of lesser thickness at the end of the group containing fewer laminations.

7 A laminated stator structure for magnetos including groups of stacked laminabar magnets each supported at one end in a perforation in said member, a plate assembly consisting of an imperforate magnet plate, and a perforate non-magnetic plate, each bar magnet being supported in a perforation in said non-magnetic plate andin contact with said magnet plate; laminated pole shoes connecting the like polar ends of said bar magnets remote from said plate assembly; spacers between said pole shoes and said plate assembly; and means for clamping the plate assembly to said bar magnets.

-- CURT F. REIS. 

